Well, first of all, thank you for posting.
I can see why they'd take that scene out, even though it'd be pretty funny for the Dursleys to meet the Weasely's for the first time. But, alas, I don't think it would be necessary for the plot. I'm sure they'll mention something about it in the dialogue. Unless, they don't explain anything like they did in PoA. Don't get me wrong. I liked PoA, but still.
At least my icon explains it.